A C BRIEFS

Degree of Polymerization and Incremental Equivalent. Chain Length Constants. Application to Poly(ethylene ... Anal. Chem. 41, 314 (1969). An Objective...
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A C BRIEFS Highlights of Articles in This Issue

Differential Kinetic Analysis of Alkaline-Earth Ions Using Stopped-Flow Spectrophotometry Rapid qualitative and quantitative analysis of Mg, Ca, Sr, and Br is achieved by using the differing reaction rates of their CyDTA complexes. Reaction rate constants are in the ratio of 1: 6.5: 96: 1660 for M g : Ca: Sr: Ba. J. B. PAUSCH and DALE W. MARGERUM, Department of Chemistry, Purdue University, Lafayette, Ind. 47907 Anal. Chem. 41, 226 (1969)

Differential Kinetic Analysis of the Metallic Elements Kinetic data are reported for more than 30 metal ions. The rate of reaction of the metal—CyDTA complexes with acid or with an exchanging metal ion is the basis for quantitative and qualitative analysis of mixtures of metal ions. DALE W. MARGERUM, J. B. PAUSCH, G. A. NYSSEN, and GREGORY F. SMITH, Purdue University, Lafayette, Ind. 47907 Anal. Chem. 41, 233 (1969)

An Automated Fast Reaction-Rate System for Quantitative Phosphate Determinations in the Millisecond Range The initial rate of formation of 12-molybdophosphoric acid from phosphate and Mo(VI) in acid medium is measured to give digital rate data proportional to the phosphate concentration, about 100 milliseconds after the reagents are mixed automatically. Concentrations of 0.1 ppm and up can be read. A. C. JAVIER, S. R. CROUCH, and H. V. MALMSTADT, University of Illinois, Department of Chemistry and Chemi­ cal Engineering, Urbana, III. 61801

Determination by Atomic Absorption of Molybdenum, Ruthenium, Palladium, and Rhodium in Uranium Alloys The mutual interference of the four elements, the effect of uranium on the absorbance values of these elements, and the development of an analytical procedure for the analysis of fission alloy form part of this investigation. J. M. SCARBOROUGH, Atomic International, Calif. 91304

Canoga Park,

Anal. Chem. 41, 250 (1969)

Determination of Oxygen-to-Uranium Ratios in Hypoand Hyperstoichiometric Uranium Dioxide and Tungsten-Uranium Dioxide A study to clarify the determination of oxygen-to-uranium ratios in I T 0 2 ± i and W - "Γθ2±χ and to present methods which have been developed for these determinations is reported. E. A. SCHAEFER and J. O. HIBBITS, General Electric Company, Nuclear Systems Programs, Cincinnati, Ohio 45215 Anal. Chem. 41, 254 (1969)

Theory of Cyclic Voltammetry for a Dimerization Reaction Initiated Electrochemically The partial differential equations are solved by combining the integral equation procedure and a finite difference method. The dimerization rate constant can be evalu­ ated from a single cyclic polarogram. MICHAEL L. OLMSTEAD, ROBERT G. HAMILTON, and RICHARD S. NICHOLSON, Chemistry Department, Michi­ gan State University, East Lansing, Mich. 48823 Anal. Chem. 41, 260 (1969)

Anal. Chem. 41, 239 (1969) Precipitation Titrations with Electrochemically Generated Lanthanum Ion. Potentiometric Titration of Fluoride and Turbidimetric Titration of Oxalate Determination of Ethanolamides in Mixtures by Differential Saponification Rates F a t t y alkanolamides are saponified in alcoholic K O H to give 2 moles of weak base for every mole of K O H reacting with one mole of amides. FRED H. LOHMAN and THERESA F. MULLIGAN, The Procter & Gamble Company, Cincinnati, Ohio Anal. Chem. 41, 243 (1969)

Determination of Nonionic Surfactants by Atomic Absorption Spectrophotometry The surfactant is precipitated as a heteropoly phosphomolybdic acid—barium complex and the molybdenum in the supernatant solution is assayed by atomic ab­ sorption. J. C. SHERIDAN, E. P. K. LAU, and Β. Ζ. SENKOWSKf, Analytical Research Laboratories, Hoffmann-La Roche, Inc., Nùtley, Ν. J. 07110 Anal. Chem. 41, 247 (1969)

Samples of fluoride ion, 0.5 to 2 mg, in 105 ml of solution are titrated with a precision and accuracy of en. ± 0.1% by use of pretitration and titration techniques to a pre­ determined end point potential. D. J. CURRAN and K. S. FLETCHER III, Department of Chemistry, University of Massachusetts, Amherst, Mass. 01002 Anal. Chem. 41, 267 (1969)

Potentiometric Determination of Carbon Dioxide Partial Pressure and pH in Ultramicro Volumes of Biological Fluids The system reported combines a microscopic cell without, liquid junction potential and a thin layer of paraffin oil as C 0 3 diffusing membrane in order to measure p C 0 3 in 10-nl volumes and the pH under controlled atmosphere in 300 pi of fluid samples. JULIO C. PITA, University of Miami School of Medicine, P.O. Box 875, Biscayne Annex, Miami, Fla. 33152 Anal. Chem. 41, 273 (1969) VOL. 4 1 , NO. 2, FEBRUARY 1969

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AC Stereochemistry of the Electrolytic Reductive Coupling of Benzaldehyde Isomer ratios have been studied under a variety of solution conditions ; electrolytic ratios are the same as the photolysis ratios except when ions which are adsorbed at the electrode—solution interface are present. VINCENT J. PUGLISI, GARY L. CLAPPER, and DENNIS H. EVANS, Department of Chemistry, University of Wisconsin, Madison, Wis. 53706 Anal. Chem. 41, 279 (1969)

BRIEFS

General Considerations Concerning Atmospheric Aerosol Monitoring with the Hydrogen Flame Ionization Detector The rate of ion formation has been studied and first-order rate constants for the ionization of sodium in five small hydrogen diffusion flames have been determined. Sodium chloride particle 0.1μ in diameter can be detected. R. WAYNE OHLINE, EDWIN THALL, and PING HWAT OEY, Department of Chemistry, New Mexico Institute of Mining and Technology, Socorro, Ν. Μ. 87801 Anal. Chem. 41, 302 (1969)

Standards for a Practical Scale of pD in Heavy Water Two new reference buffers—i.e. potassium dideuterium citrate and an equimolal mixture of sodium deuterium carbonate and sodium carbonate—are proposed as supplementary standards to be used in conjunction with a previously studied phosphate solution to fix a standard scale of pD. MAYA PAABO and ROGER G. BATES, National Bureau of Standards, Washington, D. C. 20234 Anal. Chem. 41, 283 (1969)

Gas Chromatographic Characterization by Equivalent Degree of Polymerization and Incremental Equivalent Chain Length Constants. Application to Poly(ethylene Glycol) and Ethylene Glycol Derivatives Alkyl substituents at the terminal position are shown to affect the retention of ethylene glycol and P E G by characteristic constant values, observed as deviations in retention from the parent glycols. THOMAS K. MIWA, Northern tory, Peoria, III. 61604

Regional Research Labora­ Anal. Chem. 41, 307 (1969)

Polarographic Measurement of Relative Strengths of Bronsted Acids in Pyridine. Dispersion and Solvation Effects in Acid-Base Equilibria. Analysis of Bronsted Acid Mixtures A study of the dependence upon pKa*', pK a in pyridine, and structural type of E y i in pyridine of a varied group of uncharged Brçlnsted acids with 0.1Μ EtiNClOi as background electrolyte indicates that E ' / i in pyridine is proportional to p K , p " . KEIICHI TSUJI and PHILIP J. ELVING, The University Michigan, Ann Arbor, Mich.

of

Anal. Chem. 41, 286 (1969)

Determination of Water in Nitrogen Tetroxide. Gas Chromatographic Method for Total Hydrogen Content As little as 0.1 fig of water (0.01 wt % ) can be determined reproducibly and less than 10 minutes are required for an analysis. R. F. MURACA, EDWARD WILLIS, C. H. MARTIN, and C. A. CRUTCHF/ELD, Stanford Research Institute, Menlo Park, Calif. Anal. Chem. 41, 295 (1969)

Identification of Aromatic Ketones in Cigarette Smoke Condensate Study of one subfraction representing 0.08% of the original weight of the condensate identified fluoren-9-one, the four methylfruorcn-9-ones, and seven other alkylated fluoren-9-ones. J. H. BELL, SUE IRELAND, and A. W. SPEARS, Research Division, Lorillard Corp., Greensboro, N. C. Anal. Chem. 41, 310 (1969)

Nitrogen and Oxygen Compound Types in Petroleum. Total Analysis of a 4 0 0 - 7 0 0 °F Distillate from a California Crude Oil AH compound types present in more than trace amounts were accounted for, their molecular structurers were de­ termined, and their concentrations were measured. L. R. SNYDER, Union Oil Company of California, Research Department, P.O. Box 76, Bea, Calif. 92621 Anal. Chem. 41, 314 (1969)

Analysis of Tea Flavanols by Gas Chromatography of Their Trimethylsilyl Derivatives The derivatives are separated on an 8-ft glass column packed with 3 % OV-1 supported on 60-80 mesh Gas Chrom Q, using two sets of isothermal conditions. ALBERT R. PIERCE, HAROLD N. GRAHAM, SEYMOUR GLASSNER, HOWARD MADLIN, and JORGE G. GON­ ZALEZ, Thomas J. Lipton, Inc., 800 Sylvan Ave., Englewood Cliffs, N. J. 07632 Anal. Chem. 41, 298 (1969)

An Objective Computer-Oriented Method for Calculation of Stability Constants from the Formation Function A computer program written in Fortran IV language to calculate the stability constants of simple mononuclear complexes from formation function data is described. LOUIS P. VARGA, Department of Chemisty, State University, Stillwater, Okla. 74074

Oklahoma

Anal. Chem. 41, 323 (1969) VOL. 4 1 , NO. 2, FEBRUARY 1969

.

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AC BRIEFS Differential Scanning Calorimetry as a General Method for Determining the Purity and Heat of Fusion of High-Purity Organic Chemicals. Application to 95 Compounds Described is a procedure for the cryoscopic determina­ tion of purity which uses D S C . Organophosphates, amides, ureas, carbamates, heterocyclics, chlorophenoxy acids, esters, and halogcnated compounds are analyzed. CANDACE PLATO and AUGUSTUS R. GLASGOW, Jr., Division of Food and Chemistry and Technology, Food and Drug Administration, Washington, D. C. 20204 Anal. Chem. 41, 330 (1969)

A Radioisotope X-Ray Fluorescence Spectrometer with a High-Resolution Semiconductor Detector. Analytical Sensitivity for Elements in Low Atomic Number Matrices Molybdenum samples ranging from 10 ng to 1 mg, and nickel samples ranging from 0.1 ^g to 1 mg were analyzed. T h e detection limit for Mo was 35 n g ; precision in the submicrogram range was 10-20%. SACHIO YAMAMOTA, Naval Radiological tory, San Francisco, Calif. 94135

Defense Labora­

Anal. Chem. 41, 337 (1969)

Rapid Extraction and Direct Spectrophotometric Determination of Copper with Thiothenoyltrifluoroacetone The olive brown C u ( I I ) - S T T A chelate solution in car­ bon tetrachloride follows Beer's law over the concentra­ tion range of 1.23 to 12.35 Mg of Cu per ml. Quantitative extraction is feasible with O.OOIA/ STTA between p H 2 to 5. V. M. SHINDE and S. M. KHOPKAR, Department of Chem­ istry, Indian Institute of Technology, Bombay, Bombay 76, India Anal. Chem. 41, 342 (1969)

Detection of Volatile Components in Solids and Thin Films by Gas Chromatography of Evolved Gases A technique based on evolved gas detection is illustrated with some conventional dehydration processes using C11SO4 · 5H2O and mineralogical AI2O3 • 3H 2 0 samples. G. A. DORSEY, Jr., Department of Metallurgical Research, Kaiser Aluminum & Chemical Corp., Spokane, Wash. Anal. Chem. 41, 350 (1969)

A Study of the Influence of Silicone Grease on Spectrophotometric Methods for the Determination of Fluoride Results obtained in this study proved that it is possible to use silicone grease for sealing diffusion vessels without any precautions. JAN TUSL, Research Institute for Animal Nutrition, Science and Technology, Pohorelice, Czechoslovakia

Feed

Anal. Chem. 41, 352 (1969)

Identification of Surface Functional Groups on Active Carbon by Infrared Internal Reflection Spectrometry The spectra of active carbon has been measured by 1RS in order to obtain spectrometric evidence of the nature of functional groups on the active carbon surfaces. JAMES S. MATTSON, HARRY B. MARK, Jr., and WALTER J. WEBER, Jr., Water Resources Sciences, Department of Chemistry, and Department of Civil Engineering, Univer­ sity of Michigan, Ann Arbor, Mich. 48104 Anal. Chem. 41, 355 (1969) Determination of Phosphate in Water with Tungsten-185 The 185-tungstomolybdophosphoric acid complex is ex­ tracted into an organic solvent ; the extracted tungsten activity is then counted and related to the original phosphate concentration. RICHARD Β. ΗΑΗΝ and THOMAS M. SCHMITT, Depart­ ment of Chemistry, Wayne State University, Detroit, Mich. 48202

SpectroDhotometric Determination of Copper in Alkali Metals and Hydroxides with 4,4'-Dihydroxy-2,2/-Biquinoline T h e chromogenic properties of 13 newly synthesized biquinolines are studied with regard to metal ion chela­ tion. ALFRED A. SCHILT and WILLIAM C. HOYLE, Department of Chemistry, Northern Illinois University, Dekalb, III. 60X15 Anal. Chem. 41, 344 (1969)

Anal. Chem. 41, 359 (1969) Spectrophotometric Determination of Primary Aromatic Amines with 9-Chloroacridine The method described is comparable in its sensitivity to diazotization—coupling techniques and possesses the ad­ vantage of simplified reagent preparation. JAMES T. STEWART, TERRY D. SHAW, and ANTHONY B. RAY, Department of Medical Chemistry, School of Phar­ macy, The University of Georgia, Athens, Ga. 30601 Anal. Chem. 41, 360 (1969)

Notes Determination of Water by Direct Injection Enthalpimetry The proposed method uses D I E and a temperature pulse obtained from the rapid exothermic adsorption of water b y molecular sieves.

Identification of Alkyl Aryl Sulfides in Wasson, Texas, Crude Oil Described is the isolation and positive identification of (2-methyl-l-thiabutyl) benzene (phenyl sec- butyl sulfide), and the tentative identification of three other alkyl aryl sulfides.

C. A. REYNOLDS and SISTER MARIE JOAN HARRIS, De­ partment of Chemistry, University of Kansas, Lawrence, Kans.

R. L. HOPKINS, R. F. KENDALL, C. J. THOMPSON, and H. J. COLEMAN, Bartlesville Petroleum Research Center, Bureau of Mines, U. S. Department of the Interior, Bartlesville, Okla.

Anal. Chem. 41, 348 (1969)

Anal. Chem. 41, 362 (1969) VOL. 4 1 , NO. 2, FEBRUARY 1969 .

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AC BRIEFS Fluorometric D e t e r m i n a t i o n of Pesticides A study to develop sensitive procedures for the determina­ tion of chlorinated insecticides, carbamate insecticides, and herbacides, based on the use of enzyme systems is reported. GEORGE G. GUILBAULT and M. H. SADAR, Chemistry Department, Louisiana State University in New Orleans, New Orleans, La. 70122 Anal. Chem. 41, 366

Quantitative Electrodeposition of Actinides from Dimethylsulfoxide A simple, quantitative, and fast technique for preparing sources for analytical alpha spectrometry by electrodeposition from D M S O is reported. T H O M A S H. HANDLEY and J. H. COOPER, Analytical Chemistry Division, Oak Ridge National Laboratory, P. 0. Box X, Oak Ridge, Tenn. 37831

(1969)

Application of Interrupted-Elution to C o m b u s t i o n Radio Gas C h r o m a t o g r a p h y

Anal. Cfiern. 41, 381

Correspondence

Interrupted clution allows sufficient time to ensure the complete conversion of any oluted peak and permits effective removal of any activity left in the combustion train before conversion of the next peak is undertaken.

Evidence for Coupling in Chromatographic C o l u m n s M. F. EDWARDS, School of Engineering Science, of Warwick, Coventry, Warwickshire, England

FULVIO CACACE and GIORGIO PEREZ, Laboratorio di Chimica Nucleare del C.N.R.—Istituto di Chimica Farmaceutica e Tossicologica, University of Rome, Rome, Italy Anal. Chem. 41, 368

(1969)

T h e proposed method differs from those previously de­ scribed in sample preparation, sample size, lack of cru­ cible bath, automatic temperature programming, and the products formed in the inert gas fusion. CAROLYN S. MacDONALD, MAYNARD E. SMITH, and GLENN R. WATERBURY, University of California, Los Alamos Scientific Laboratory, Los Alamos, Ν. Μ. 87544 Anal. Chem. 41, 372

(1969)

M a g n e s i u m Spinel Interferences in A i r - A c e t y l e n e vs. Nitrous Oxide-Acetylene Flames in Atomic Absorption Spectrometry In this study, magnesium was chosen as the analyte, and aluminum as the major interfèrent along with titanium and zirconium. Proper selection of flame parameters minimizes the effect of interferences. W. W. HARRISON and W. H. WADLIN, Department Chemistry, University of Virginia, Charlottesville, 22901

of Va.

The Foxboro

Com-

Anal. Chem. 41, 377

(1969)

D e t e r m i n a t i o n of Silicon in Siloxane Polymers a n d Silicone-Containing S a m p l e s Employing Alkali Fusion Decomposition M e t h o d s Use of K O H found to give polymers. An which converts

in place of N a O H in direct fusions was better recovery of silicon from siloxane alcoholic alkali pretreatment step is used siloxane bonds to silanolates.

JAMES H. WETTERS and ROBERT C. SMITH, Corporation, Midland, Mich. 48640

Dow

Anal. Chem. 41, 379

Circle No. 54 on Readers' Service Card

(1969)

Aids for Analytical Chemists E. A. MERSHAD, M. L. CURTIS, J. Y. JARVIS, and W. R. AMOS, Mound Laboratory, Miamisburg, Ohio 45342 Anal. Chem. 41, 384

(1969)

Perfluoroalkyl-s-Triazines a s M a s s Calibration S t a n d a r d s for Time-of-Flight Spectrometry R. HERBERT WALLICK, GERALD L. PEELE, and JOHN B. HYNES, Research Department, Liggett and Myers, Inc., Durham, N. C. 27702 Anal. Chem. 41, 388

(1969)

A System for Continuously M o n i t o r i n g Hydrogen Chloride Concentrations in Gaseous Mixtures U s i n g a Chloride Ion-Selective Electrode T. G. LEE, National D. C.

Bureau

of Standards, Washington, Anal. Chem. 41, 391

The use of CrB for the elecfrochemical generation of Cr(VI) for use in titrations is investigated as an extension of previous work with refractory metal borides. Center,

Anal. Chem. 41, 383

(1969)

(1969)

C h r o m i u m Boride as an Electrochemical Générant for T i t r a t i o n s with C h r o m i u m ( V I )

K. S. FLETCHER III, Research pany, Foxboro, Mass. 02035

University

G a m m a Pulse Height Determination of P l u t o n i u m - 2 3 8 in Solid Wastes

D e t e r m i n a t i o n of Oxygen in Refractory Oxides

Anal. Chem. 41, 374

(1969)

Corning (1969)

Determination of Dissolved Oxygen in Hydrocarbon Solvents U s i n g Gas—Liquid C h r o m a t o g r a p h y with Electron Capture Detection P. T. FORD, Shell Research Ltd., Thornton Research ter, P. 0. Box 1, Chester, CHI 3SH, England Anal. Chem. 41, 393

Cen(1969)

A M e t h o d of Background Correction for Direct R e a d i n g Optical Emission Spectroscopic Trace Analysis U s i n g Offset Exit Slits J O H N A. LEYS, 3M Central Research Center, St. Paul, Minn. 55101

Laboratories,

Anal. Chem. 41, 396

3M (1969)

S m a l l S a m p l e H a n d l i n g in Laser R a m a n Spectrometry S. K. FREEMAN, International Flavors & Fragrances, R & D Center, Union Beach, N. J . a n d D. O. LANDON, Spex Industries Inc., Metuchen, N. J. Anal. Chem. 41, 398 VOL. 4 1 , NO. 2, FEBRUARY 1 9 6 9 ·

(1969) 17 A